Low frequency oscillator with negligible resistance



0d. 26, 1937. R THOMPSON 2,096,867

LOW FREQUENCY OSCILLATOR WITH NEGLIGIBLE RESISTANCE Filed Sept. 26, 1934 2M 22% am Patented Oct. 26, 1937 LOW FREQUENCY OSCILLATOR. wl'rn NEGLIGIBLE RESISTANCE Robert R. Thompson, Houston, Tex., assignor to Standard Oil Development Company, a corporation of Delaware Application September 26, 1934, Serial No. 745,565 7 ;It is known that the construction of low 2 z 2 2 2 2 2 2 5 frequency oscillators is attended with difiiculties (k MW) +1 W (k +t W because of the fact that as the frequency is de- Where E= 'm force apphed at 7 creased the ratio of the resistance to the reactance R=the resistahee P the resistance of coils increases, thus resulting in a broad resoof the 4 wound on frahle I 10 nance peak for the system, which broad resonance e ratio of the folfce 10 peak prevents sharp tuning. These difliculties Induced hcross 4 F the Veloclty are not as great in the case of mechanical systems of Vibrahoh of the 4 relative to as in the case of electrical systems, but they are the magnet 5 V formidable as a rule never-the-less. T=the damping Of the mechanical System 15 It is an object of this invention to overcome Consisting of the spring 2 h 10114 the above mentioned difliculties and to permit w=the impressed e cy mu t plied b of building electrical or mechanical oscillators, 21F either low or high frequency, with zero or negligik=the Sprlng Constant Of p g 2 ble resistance or damping pressed in dynes per centimeter ex- The invention will be fully understood from the tension of the Spring 20 following description taken in connection with M=the mass of the Coil 4 the accompanying drawing in which latter the L=the sum of inductance l0 and the figure is a schematicrepresentation of a preductahce 0f the c011 4 ferred apparatus for carrying out the invention. Finally 5 Referring particularly to the drawing a mej=. /-1 25 chanical oscillatory system is shown comprising a coil f ame I which is Suspended y means of Thus it is seen that the current I can be made a helical sprin 2 rom a suppo t n case A large by adjusting the constants in the denomicoil 4 is wound upon the coil frame I. If desired hator of t above equation so t t t t fagthe helical Spring 2 can be replaced by a leaf tors approach zero. Since R is the sum of the 30 Sp and Some Of the advantages W be resistance II and the resistance of the coil 4, tain d- A magnet 5 is Supported by the ease 3 we see that the factor subtracted therefrom repinside of the coil frame I. There is thus provided resents a negative resistance which has been a mechanical oscillatory system of predetermined troduced into the electrical circuit by the coufrequency operative to produce a varying current pling to the mechanical system. Also, since L 35 of electricity. While the magnet 6 has been derepresents the total inductance of the circuit, it scribed as the stationary system and the coil 4 15 e that the factor follewihg L in e deas the oscillatory element it will be understood homma'tor of the above equahoh represents a that the magnet 6 can be resiliently Suspended negative reactance for all frequencies less than 40 and the coil 4 can be rigidly supported and some k 40 of the advantages of the invention will be re- V; tamed The elements I to 6 incluslve constitute which is the natural frequency of the mechanical a vibratory system.

. system.

An electrical circuit is connected to the me- It is possible therefore, with this device, to 45 chflmcalvibratory FYStem tfhltough themductance construct resonant electrical circuits with very coil 4. The electric circuit includes a source of Small decrement at very low f u i Com os l at c t a d an ammeter A versely, it is also possible with this device to conriable inductance l0 and a variable resistance H tr m; a very sharply resonant mechanical ysare connected in series in the circuit. tem. 50

v I v 3 Claims. (01. 178-44) This invention relates to an improved method Computation shows that the current I is: and apparatus for overcoming resistance in elec- I: v

trical; systems and for'overcoming damping in mechanical systemsi Resistance is overcome in the electrical system or damping is overcome in the mechanical system by electrically connecting the electric circuit with the mechanical vibratory system and adjusting the constants of the electrical and mechanical systems so as to introduce negative electricalresistance and/or negative damping which cancel the electrical resistance of the electrical system and/or the mechanical damping of the mechanical system.

By the construction described the electrical circuit and the vibratory mechanical circuit are coupled in sucha Way that a current in the electrical circuit produces vibration in the mechanical circuit, or vibrations of the mechanical circuit produce currents or voltages in the electrical circuit. The impedance to currents in the electrical circuit is thereby changed in such a Way that negative resistances, and positive or negative reactances will be introduced; and the impedance to motion of the mechanical circuit is changed. so that negative mechanical resistances, and negative or positive mechanical reactances are introduced into the mechanical cir.-'

cuit by the currents which flowin the electrical circuit. 1

Various changes may be made within the scope of the appended claims in which it is desired to claim all-"novelty inherentin the invention as broadly as the prior art permits.

I claim: 5 1. A system, comprising a source of alternating current disposed in an electric circuit, a mechanical vibratory system including a magnet of fixed strength, an inductance coil, means supporting the magnet and inductance coil to permit oscillatory movement relative to each other, the inductance coil being connected in the electric circuit, an inductance and a resistance connected in series in the electric circuit, and means for relative adjustment of the constants of the electric circuit and of the mechanical system.

2. A system, comprising a source of alternating current disposed in an electric circuit, a mechanical vibratory system including amagnet of fixed strength, an inductance coil, means resiliently suspending the coil for movement with respect to the magnet to permit the coil to oscillate with respect to the magnet, the inductance coil being connected in the circuit, an inductance and a resistance connected in series in the circuit, and means for relative adjustment of the constants of the electric circuit and of the mechanical system.

3. A system, comprising a source of alternating current disposed in an electric circuit, a mechanical vibratory system including a magnet of fixed strength, an inductance coil, means resiliently suspending the coil to permit oscillatory movement with respect to the magnet, the inductance coil'being connected in the circuit, and a variable inductance and a variable resistance connected in series in the-circuit for relative adjustm'e nt of the constants of the electrical circuit and of the mechanical system. 7

ROBERT E; THOMPSON. 

